Refrigerating apparatus



June s,-1937. E HEWMAN 2,083,378

' INVENTOR, PMR-D IiP/WVM ATTORNEY.

June 8i, i937.

.5 @gliHI|||||||||||||||||U E. HEITMAN REFRIGERATING APPARATUS Filed Aug. 17, 1935 4 sneets-snet 2 ATTORNEY.

June 8,- 1937. E, HE|TMAN 2,083,378

REFRIGERATING APPARATUS 'Dwaiez: #sir/wily ATTORNEY. l

June 8, 1937. E. HEITMAN 2,083,378

REFRIGERATING APPARATUS Earl/1am M ATTORNEY. l

A Patented June 8, 1937 l PATENT OFFICE REFRIGERATING APPARATUS Edward Heitman, Detroit, Mich., assigner to Kelvinator Corporation, Detroit, Mich., a corporation of Michigan Application August 17, 1933, Serial No. 685,531

Claims.

The present invention relates to refrigerating systems and particularly to the control of the temperature of the cooling element of the refrigerating system.

5 Normally the cooling element of a refrigerating system, particularly the household type is maintained between predetermined temperature limits, providing a mean temperature which is desirable for proper food preservation. Usually a freezing compartment is .provided for congealing desserts such as ice cream, sherbets and the like or for freezing water, and, at the temperature normally maintained, the ice cream or the like or water will -freeze over a period of time. It is often desirable l5 to hasten the freezing. At this temperature, at

least a portion of the cooling element of the refrigerating system must be maintained at a temperature lower than 32 F. and therefore moisture collects on the cooling element and freezes. there- ,l on in the form of a frost. In the course of time,

this frost builds to such a thicknessA as to materially impair the eiiicient operation of the refrigerating system. It is an object of the present invention to provide a refrigerating system and a control mechanism therefore which-can bemanipuiated for obtaining either a higher or lower han normal temperature of the cooling element .ar cooling unit and which mechanism is arranged to restore the cooling element to its normal tem- 30 perature after a temporary pliase of operation of the system has takenplace.

Other and further objects and advantages will be apparent from the following disclosure, reference being had to the accompanying drawings 3;, wherein preferred forms of embodiment of the 'present invention are clearly shown.

In the drawings:

Fig. 1 is a longitudinal cross sectional view of the household type refrigerating cabinet show- 40 ing a refrigerating system disposed therein;

Fig. 2 is a longitudinal cross sectional view of the refrigerating cabinet with the refrigrating -mechanism therein, the section being taken substantially at right angles to that of Fig. 1;

` 45 Fig. 3 is a front view of the control panel;

Fig. 4 is a sectional view of a controller of the system;

Figs. 5 and 6 are sectional views taken on lines 5-5 and 6 6 respectively of Fig. 4;

Fig. 'l is a sectional view taken on line 1-1 of Fig. 6; v y.

Fig. 8 is a fragmentary sectional view showing part of the mechanism shown in Fig. 4 but show- 55 ing'the same in a different position;

Fig. 9 is another sectional view of the controller;

Fig. 10 is a sectional view taken on line iii- Ill of Fig. 4;

Fig. 11 is a sectional view taken on line i I-I I of Fig. 9; f

Fig. 12 is a -sectional view taken on line I2-I2 of Fig. 9 but on a somewhat larger scale;

Fig. 13 is a sectional view taken on line I3-l3 Fig. 14A is a fragmentary bottom view taken on line l4A--I4A of Fig. 9 with the electrical plug removed; i

Fig. 14 is afragmentary sectional view of a modified form of the invention;

Fig. 15 is a sectional viewof the modified form shown in Fig. 14 looking in the opposite direction, the section being taken through another portion of the controller;

Fig. 16 is a sectional view taken on line Iiii6 o'f Fig. 14 and Fig. 1'? is a"sectional view taken on line il-i'l of Fig. 14.

Referring first to Figs. 1 and 2, for the purpose of illustrating the present invention, there is shown a refrigerating cabinet 20 of the household type having insulated food compartment 2l and amachine compartment 22. The cooling element or unit is herein shown as an evaporator 24 forming a freezing -compartment containing trays 26. The flow of liquid refrigerant to-the evaporator 24 is controlled by an expansion valve 21 of any suitable type, the liquid refrigerant being conducted thereto by a liquid line 28. Gaseous refrigerant is withdrawn from the evaporator 24 through a pipe 29. Disposed within the machine compartment 22 is a compressor 3| which is driven by a motor 32 by a belt 33. Gaseous refrigerant from the pipe 29 is conducted to the low pressurenside, of the compressor 3|, is compressed by the compressor 3| and forced into a condenser 34. The condenser is placed so as to be cooled by a fan driven by the motor 32. The compressed refrigerant is condensed within the condenser and liquefied and then passed into a receiver 36 from whence it is conducted .to the expansion valve 21 through the pipe 28. During normal operation of the system the compressor 3| circulates such amount of refrigerant through the evaporator 24 so as to maintain the air within the cabinet "2U at a temperature desirable for proper food preservation and in the present illustration the flow of refrigerant is controlled by starting and stopping the compressor 3 I, the compressor being started when a predetermined thermostatic tube 43.

maximum high temperature is reached and stopped when a predetermined minimum low temperature is reached. For economic purposes, at this temperature the water or sherbet or the like which may be contained within the trays 25 will freeze relatively slowly. At times it is desirable to hasten this freezing. When operating at normal temperatures, moisture from the food and moistures which enter the box or the cabinet when the door is open, condenses on the evaporator and freezesthereon. In the course of time this frost will become so thick as to impair refrigeration.

. In accordance with the present inventiony there is provided a controller 38 for the system which normally maintains the evaporator between predetermined high and low temperature limits and which mechanism may be manually set to obtain temporarily a low temperature of the evaporator. After thisl temporary phase of operation has taken place, the controller functions to automatically restore the system to the normal control. The controller also includes means for manually adjusting the same to temporarily obtain a high temperature of the evaporator and after this predetermined temporary phase of operation, the system is restored to the normal control. This controller is preferably carried on the front of the evaporator by a plate 48 and comprises a switch 4|, a thermostatic bulb 42 which is connected to the switch by a tube 43. The switch comprises a main frame 45 formed of material such as bakeiite which is undercut as at 45 and has a portion which extends through an opening 48 in the panel. The switch-is secured to the panel 48 by clamping the panel 48 between the frame 45 and an indicia plate 41 by a screw 48. A second frame 49 which may be also bakelite is secured to the frame 45. Frame 49 carries contacts 58 and 5| which are spaced from one another and are suitably connected with a socket 52. 'I'he switch also comprises a cup shaped casing 54 in which there is disposed a metallic bellows 55 which is connected with the The bellows 55 is pro.- vided with an externally threaded fitting which extends through an opening 55 in cup 54 and the bellows is clamped to the cup bya nut 51 which is threaded on the fitting.

A bracket 59 is secured to the frame 49 and forms a knife edge fulcrum 58 for a lever 5|. Lever 5| is conically depressed as at 52 to form a socket for receiving the point 53 on the top oi' the bellows 55. A volatile fluid is contained within the thermostat 42, tube 43 and bellows 55 and is therefore responsive to changes in temperature for causing expansion and contraction of the bellows 55. When the temperature at bulb 42 increases, bellows 55 will expand causing up-l ward movement of the point 53 and consequently lever 5I. Lever 5| is normally urged downwardly by a coil spring 55. Two ears 55 and 51 extend from opposite sides of the lever 5| and are bent yvupwardhr and each of these ears is notched as at 58 and 59 to receive knife edges of levers 18 and 1| respectively. The ends of levers 18 and 1| are bifurcated so that each is provided with two knife edges.

Levers 18 and 1| extend 1 laterally from opposite sides of the ears 55 and 58 and 5|. When the ears 55 and 51 are in the -position shown in Fig. 4, spring 13 holds the levers 18 and 1| in a position in kwhich contact 15 does not bridge contacts 58 and 5| but when these ears are in the position shown in Fig. 8, spring 13 holds the levers 18 and 1| in a position whereby the contact 15 bridges contacts 58 and 5|.

Bracket 59 also pivotally carries a lever 11. This lever 11 includes depending ears 18 which are fulcrumed at pivot 19 to bracket 59. A screw 8| extends freely through the lever 11 and the head thereof forms an abutment for lever 13, the lever 11 being forced upwardly against the underside of the head by a coil spring 82. Depending from opposite sides of a lever 11 are ears 83 which form fulcrum points for the lever 18 and the outer end of lever 11 includes a downwardly extending finger 85 which forms a ystop for limiting the upward movement of lever 1|. As the pressure within the bellows increases, the lever 5| and ears 55 and 51 will be moved upwardly causing the innerends of levers 10 and 1I to be moved upwardly. These levers 18 and 1| will fulcrum about the ears 83 and finger 85 causing the outer ends of the levers to move downwardly and after these levers are moved beyond the dead center position with respect to one another, the coil spring 13 will pull the outervends of the levers downwardly to the position shown in Fig. 8. Current will now ow through the motor 32 to drive the compressor 3| and gradually reduces the temperature in the evaporator 24. The thermostat bulb 42 is in intimate thermal contact with the evaporator and is therefore responsive to the temperature thereof. As the temperature within the evaporator decreases, the temperature of the volatile fluid in the bulb 42 will decrease causing a reduction of pressure within the bellows 55 'and a gradual contraction thereof. 'Ihe spring 55 urges the lever 5| downwardly and when the pressure within the bellows decreases, the lever 5| will move downwardly. Substantially directly underneath the ears 83 are fingers 81. These fingers are formed integrally with the bracket 59 and provide lower fulcrums for the lever 18. As the ears 55 and 51 are moved downwardly, the inner ends of the levers 18 and 1| will also be moved downwardly causing the lever 18 e to fulcrum about fingers 81 and also cause the outer ends of the levers 18 and 1I to moveupwardly. When the ears move downwardly to such an extent that the levers 18 and 1| move beyond their dead spring 13 will cause the 4outer ends of the'levers to move upwardly quickly to thereby separate y contact 15 from contacts 58 and 5|. By turning the screw 8| downwardly, the lever 11will be to` their dead center positions because of the lowering of the fulcrum points of lever 18 formed by the ears 83. In this manner the range between the high and low temperature operation of the switch is reduced and thus the degrees of temperature between the cut in and cut out of the motor can be regulated.

` The mean temperature of the evaporator is controlled by adJusting the tension of the spring 55. The spring 55 is connected at itslower end to a vertically moving bracket 98. The two upper and. lower horizontal extensions 9| and 92 are threaded to receive a screw 34. The bracket 98 includes an extension which slidably engages a stationary bracket 96 for guiding the bracket 90. The bracket 96 is secured to the frame 49. The shank 98 of the screw 94 extends through the frame 46 and has its outer end deeply grooved as at 99. An externally grooved bushing |00 is longitudinally slidable on the grooved end 99 and shank 98 andis adapted when rotated to rotate the shank 98. Bushing |00 extends through the indicia plate 41 and is secured to a knob |0|. Knob |0| forms a pointer |02 which is arranged to register with the indicia formed on the plate 41. A disk |03 is carried on a shoulder |04 of the bushing |00 and a saucer type disk |05 formed of iiexible material and having the ends thereof serrated and disposed between disks |03 and the bottom of plate 41 for the purpose of irictionally restraining turning of the knob |0| and shank'98. The knob |0| can however be turned at will and by turning the knob and consequently shank 98 the bracket 90 is raised or lowered in order to decrease or increase the tension of the spring 65. If a colder temperature is desired in the cooling unit, the knob is moved from. the No. 1 position in a clockwise direction and this causes a raising of the bracket 90 and consequently a decrease in the tension of the spring 65 which has the eiect of decreasing its resistance to the upward move- Cil ment of the bellows whereby the switch will operate to close the motor circuit at a lower pressure in bellows 55 and bulb 42. Consequently the motor will be started when the evaporator 24 is at a relatively lower temperature. In this manner the evaporator will operate between lower limits of temperature.

Referring to Figs. 12 and 13, it is to be seen that a plate |01 having grooves is geared to the grooved end 99. This plate |01 is cut out at |08 so as to receive an upward extension |09 of a cam I0. This cam |0 is rotatably mounted on the shaft 99 and is held in position by a split washer Cam ||0 at one side thereof is provided with a projection ||3 which is arranged to engage either side of a stop ||4 formed in the frame 45 (see Fig. 6). By turning the knob |0|, the plate |01 and cam. ||0 are rotated, the cam |0 being rotated by the engagement of the plate |01 with the upstanding extension |09.v However the range of movement of the knob |0| is limited to less than 360, namely from the point No. 1 to the point No. l2` (see Fig. 3) by reason of the fact that the projection ||3 will engage opposite sides of the stop |4. In this manner the range of movement by which the housewife can adjust the tension of the spring is limited so that it is impossible for her to change the adjustment to such a degree as to cause inefiicient operation of the refrigerating apparatus. When assembling the switch, the tension of the spring 65 is adjusted by turning the end 99 directly before the plate 41, bushing |00 and knob |0| are applied.` The tension of the spring is adjusted so as to give normal operation of the refrigerating apparatus when the knob |00 is in its No. l position. The

cam ||0 is then,placed in position and the plate |01 is next assembled. This plate |01 is provided with a pointer ||5 and indicia numbers 1 to 12 are provided on the top of frame 45. Then the cam ||0 is Vplaced in a position in which the pointer ||5 registers with No. 1 on the frame 45. Then the plate |01 is placed in position and since it is geared to the grooved end 99, it must be properly placed over the end of the grooved end 99 so that its cut out portion |09 registers with the extension |09 on cam ||0. The bushing |00 disks |03 and |05 are next assembled and then the indicia plate 41 is secured tightly in position by screw 48.. The knob |0| is then suitably secured to the bushing |00 in a position in which its pointer registers with No. 1 of the indicia on plate 41. Due to the various characteristics of the reirigerating systems and the variation in insulation of the cabinets, it may be desirable to adjust the switch because the proper temperature cannot be obtained throughout the range of adjustment of the knob |0|. In that case the knob |0|, the plate 41, the bushing |00, the disks |03 and |05 and the plate |01 are removed and the tension of the spring is readjusted by turning the knurl 99. These parts are then reassembled as previously described.

A manual starting and stopping switch and an overload circuit breaker are also incorporated in this switch and will now be described, reffA erence being made particularly to Figs. 9, 10 and 11 of the drawings. The circuit to the motor passes through contacts ||6 and I|1 which are spaced from one another and arranged to be bridged by contact ||0 of a snap acting switch. The snap acting switch comprises a lever ||9 which is channel shaped and is pivoted to a pin |20 carried by the bracket 59. The right end of the lever ||9, as viewed in Fig. 9, carries a fulcrum pin |22 which is connected to a push and pull arm |23 having a handle |24 for manipulating the same. This arm |23 is arranged to raise and lower the lever ||9. The opposite end of the lever ||9 carries a fulcrurn pin |25 Y to which is pivotally mounted a lever |26. The

left hand end of the lever |26 carries an insulating block |21 which in turn loosely carries the movable contact H8. The fulcrum pin |22' for arm |23 pivotally carries a lever |28 having an upright ear |29 to which there is attached a spring 130. The opposite end of the spring |30 is connected to the Aleft hand end of lever |26. By forcing downwardly on the arm |23 by the knob |24, the fulcrum pin |22 will be moved downwardly and the lever ||9 is moved in a clockwise direction about pivot |20 causing the left hand end of lever |26 to be moved upwardly. The right hand end ofthe lever |26 at this time being restrained from upward movementby a stop |30. When the levers ||9 and |26 are moved beyond their dead center position with respect to the coil spring |30, the coil spring |30 will quickly move the outer end of lever |26 downwardly to cause a quick engagement of contact H0 with contacts ||6 and ||1. By pulling upwardly on the knob |24, the fulcrum pin |22 will be moved upwardlyA and the lever |9 will be moved in a counterclockwise direction {orcing the right hand end of lever |26 downwardly and, when the levers ||9 and |26 are moved be yond a dead center position with respect to the coil spring |30, the coil spring will quickly move the left end of the lever |26 upwardly to quickly separate contact ||8 from contacts ||6 and ||1.

The circuit from the motor passes through a heating coil |35 (see Fig. 14) which is disposed in a housing |36 formed in the underside of frame 49. A metal screw |31 is threaded through the top wall of the housing |36 and into the heating coil |35. A ratchet |38 (see Fig. 9) has its stem extending into and soldered to this screw |31. A plate |40 is disposed between the top side of the frame-49 and below the snap acting manually operated switch. This plate |40 includes an arm |4| of resilient material having at its outer end a hook |42 which is arrangedto engage with a tooth of the ratchet |38. A spring 45 nomical factory adiustment.

` |43 has one end thereof connected with the bracket 58 and the other end to an upwardly extending arm |45 on the plate |40. 'Ihe spring |43 normally tends to move the plate |40 to the 5 left as viewedlin Fig. 5 but is normally restrained from this movement by the hook |42 engaging a tooth in the ratchet |38. If however the solder connection between the stem of ratchet |38 and the screw' |31 is melted sufficiently to permit the j() rotation of ratchet |36, the spring |43 will move the plate |40 to the left. The plate |40 is provided with an upwardly extending ear |46 which is arranged to engage a downwardly extending ear |41 formed ,on the lever ||6 to the right of l5 the pivot point |20 as viewed in Fig. 9. Therefore when the plate |40 is moved by the spring |43, the ear |46 on the plate |40 will engage the ear |41 on the lever ||9 and rotate the lever ||8 in a counterclockwise direction which in turn 'will cause a separation of contact ||8 from c`ontacts ||6 and ||1 as above described. Should the motor require an excessive amount of current for a predetermined length of time as for example, should the motor stall, the current flowing in coil |35 will heat the screw |31 sufficiently to cause melting of the solder betweenit and the stem of ratchet |38 whereby to release the plate |40 to the action of the spring |43 to break the circuit of the motor by separating contact 6 from ||6 and ||1. By again pushing inwardly on the arm |23 by a knob |24 the switch can be reset after the solder has rehardened but this should not be done until the defect has been remedied. -From the foregoing it can be seen that there 'is provided a switch which provides for manually starting and stopping the refrigerating apparatusand for controlling the temperature of the evaporator so as to maintain the food com- 40 partment between predetermined high and low temperature limits. The temperature regulator is readily accessible which permits a temperature adjustment within certain limits but cannot be moved to such an extent as to disturb the eco- The contacts of the temperature regulator and the manually controlled switch and the overload circuitbreaker heater coil |35 are all connected in series relation and therefore only one circuit passes 50 through the entire switch.

In order to temporarily obtain a higher than normal temperature of the evaporator as for example for the purpose of permitting the frost on the evaporator to melt and in order to obtain 55 temporarily a lower than normal temperature for quick freezing or congealing a substance within the 'trays 26, there is incorporated in the switch 4|, mechanism which is manually operable for obtaining eitherthis higher or lower temperature 60 and which mechanism automatically restores the system to the normal control after completion of the temporary phase of operation. A' shaft 4| 50 is journalled in opposite sides of the frame to which there is fastened an operating mem- 65 ber |5| having an operating knob |52. 'I'his knob extends through an opening |53 in the indicia plate 41' and is used for oscillating the shaft |50. A cam |55 is secured to the shaft |50 and disposed on one side of the member |5|. This 70 camis provided with lugs |56 and |51 spaced from one another. The upwardly extending ear 61 of lever :6| forms an arm |58 and has its extreme end extending between the lugs |56 and |51. These lugs are spaced such a distance from 75 one, another that the arm |53 will engage neither when the shaft and cam i' 55 are in the neutral or normal position shown in Fig. 4. If the knob |52 is moved to its extreme right hand position as viewed in Fig. 4 and as shown in Fig. 8, the lug |51 will engage the underside of arm |56 and will cause the lever |6| to be raised upwardly and in case the snap switch is not closed, it will raise the lever 6| to close the snap switch and thereby complete the circuit to the motor through contacts 50, 15 and 5|; or lf thevknob |5| is moved to its extreme left hand position,

the lug |56 will engage the upper side of arm |58 and force the lever 6| downwardly and if the switch is not open it will move the lever 6'| far enough to open the circuit by separating contact 15 from 50 and 5|. On the opposite side of member |5| there is provided a second cam |60 which is also secured to the shaft |50. This cam is provided with a nose |6| and a nose |62 which cooperate respectively with the ends of leaf springs |63 and |64. Leaf springs |63 and |64 'are attached to the casing 45 by screw |66 and bolt |61. These springs are normally urged 'toward one another and the tension of spring |63 is adjusted by a screw |69 and the tension of spring |64 is adjusted by a screw |10. These screws are threaded into a plate |1| which is connected to the frame 45 by screw |66 and bolt |61. In Fig. 7 the mechanism is shown in its neutral position. If the knob |52 is moved to its extreme right hand position, the nose |62 will be moved to its dotted line position in` Fig. '1 and in order to return the cam |60 to its neutral position, the nose |62 must ride over the nose of the spring |64 and overcome the resistance of the spring. I'f the knob |52 is moved to its extreme left hand position,l the-nose |6| willbe moved to the opposite'side of the nose on the spring |63 and in order to return the cam |60 to its neutral position the nose |6| n'iust ride over the end of the nose of the spring |63 and thereby overcome the resistance offered by this spring.

In order to obtain an abnormally low temperature of the evaporator the knob |52 is swung to the position shown in Fig. 8. This will cause the closing of contact 15 with contacts 50 and 5| and will cause the nose |62 of cam |60 to be moved to its dotted line position in Fig. 7. The spring |64 at this time will resist the counterclockwise movement of the cam |60 because it is necessary for the nose |62 to ride over the nose of the spring |64 and therefore the downward movement of the arm |56 and the lever 6| is resisted. Consequently a low pressure must be obtained in the bellows before the lever 6| is moved beyond the dead center position of snap acting levers 10 and 1|. In other words at this time the spring |64 vcounteracts the tension of spring 65. Since a low pressure is necessary in bellows 54 in order to open the switch, a low temperature mustbe attained at the evaporator. At this time the cam will be rotated to its neutral position as shown in full lines in Fig. 7 in which position, due to the spacing of lugs |56 and |51, the spring |64 is no longer effective. Therefore at the completion of the temporary phase of the lower than normal temperature op` |6| to slide underneath the nose of spring |63 whereby the spring 4|63 will resist clockwise movement of the cam |60. At this time, the arm |58 and lever 6| are resisted in their upward movement by the enect of spring |63 since'tlie spring |63 resists the clockwise movement of nose |6|. In other words the spring |63 augments the effect of spring 65 and consequently a high pressure must be maintained in the bellows 55 before the 10 lever moves the snap acting levers 10 and 1| beyond their dead center position. Since a high lpressure is necessary in bellows |55 it follows that a high temperature must be attained at the evaporator and the adjustment of the tension of spring |63 by screw |69 is such that the temperature of ahe evaporator is raised beyond the melting point of the frost thereon so that the frost is melted before the snap switch operates to re- I close contact 15 with contacts 50 and 5I. When the snap switch moves to reclose the contacts the nose |6I of cam |60 will have moved to its neutral position in which position the arm |58 will not engage either of lugs |56 or |51 in its normal operation. Thus it will be seen that at the completion of the temporary phase of higher than normal temperature, the restored spring |63 will no longer be effective to augment the tension of spring 65 and the system will be under the control of the spring 65 and will resume its normal operation.

Means are provided for compensating the resilient effect of springs |64 in accordance with the adjustment of the tension of spring 65 and in this means comprises the cam |I0 `(see Figs.

7 and 12) which is in engagement with the end of plate |1I which carries the adjusting screws |69 and |10. Cam ||0 is actuated with the' shank 98 of screw 94 by the knob I 0|. knob |0| is rotated in a clockwise direction to decrease the tension of spring 65, the resilient plate 1| is forced downwardly by the cam ||0 causing the screw |69 to increase the tension of spring I 63 and cause the screw |10 to decrease the tension of spring |64. In this manner the differential between spring |64 and spring 65 is maintained constant and the differential between spring |63 and spring 65 is maintained constant, regardless ofthe position of the knob I0|. In other words if the knob is moved from the No. 1 position to the No. 6 position for example, which in effect causes a decrease in the tension` of spring 65 and which will allow the switch to close at a lower pressure, concurrently the tension of spring |63 is increased sufciently to compensate for the decrease in the tension of spring 65 whereby the effective resistance of these springs 65 and |63 is maintained constant and therefore the pressure in the bellows 54 mustV be raised to a given temperature at all times when knob |52 is in defrosting position, to overcome the effective resistances of springs and |63 regardless of the position of the knob |0I; likewise movement of knob |0| from its No. 1 position to its No. 6 position, causes a decrease 85 in the tension of spring |64 to compensate for the decrease in tension of spring 65 whereby the effective resistance of these springs 65 and |64 is maintained constant. The effect of the compensator is to insure a temperature of the evaporator above the melting point of the frost thereon when the knob |52 is moved to its defrosting position although the temperature controlling knob |0I is in its coldest temperature position,

v No. 12. The same is true with regard to the quick freezing position. Although the temperature If the,

controlling knob |0| is in its extreme warmest position the effective resistance of the combined action of springs |64 and 65 assures the same lower than normal temperature as when the knob is in its No. 12 or coldest position.

According to the embodiment of the invention just described the mechanism was constructed so that one knob only was necessary for moving the mechanism to either of its lower or higher than normal control positions. In accordance with the modification shown in Figs. 14, 15, 16 and 17 separate knobs are provided. It will be recalled that upward movement of the lever 6|v ,causes the closing of the automatic switch and downward movement of the lever 6| causes vthe opening of the automatic switch. .The spring 263 shown in Fig. 14 and the spring 264 shown in Fig. 15 have the same effects as springs |63 and |64 shown in the Fig. 7. The knob |12 in Fig. 14 is in its ineffective position and to become effective it must be moved to the left. 'I'his knob is formed integral with a segment |13 and this segment is carried for oscillation on a shaft |8|. The segment |13 is provided with a groove |14 for receiving an arm 258 of the lever 6|. The segment |13 is notched at |15 to receive the end of a screw |16. The spring 263 is interposed between a nut |11 and astationary abutment |18 carried by the frame 45. As shown in Fig. 14 the spring urges the screw |16 to the right causing the shoulder |19 of the segment to be held against an abutment on the casing 45. When the knob |12 is moved to the left, it causes counterclockwise rotation of segment |13 whereby the point of the screw |16 will be moved below its dead center position with respect to the axis of the segment and the left hand end of the screw. This will causev the shoulder |82 of the segment to engage an ear |83 of the arm 258 causing the arm 258 and the lever 6| to be moved downwardly and if the switch is not open will cause the lever 6| to move downwardly far enough to open the switch. In that position the spring 268 will resist the upward movement of arm 258 and lever 6| and consequently will increase the resistance to the expansion of bellows 55 whereby a high temperature must be attained rat the evaporator before the pressure in the bellows is suiiicient to overcome the resistance of springs 65 and 263. During the upward movement of the arm 258 the right hand end of screw |16 will moved above its dead`center'position and will hold the shoulder |19 of segment |13 against abutment |80 and hold the shoulder |82 out of range of movement of thev arm 258. Therefore after the temporary phase of abnormal high temperature the system is restored to the normal control of the spring 65.

The action of spring 264 is the reverse of spring 263. In Fig. 15 the switch is shown as being under normal control. A knob |85 projects through the plate 41 and is formed integral with a segment |86 carried by the shaft |8|. Segment |86 is provided with a groove |89 for the free movement of arm 258 Segment |86 is formed with a notch |90 similar to the notch |15 in segment |13 and receives the point of a screw ISI. 'I'his screw carries a nut |93 and the spring 264 is interposed between the nut |93 and a stationary abutment |94 carried by 'the frame 45. During normal operation of a re- -frigerating system the mechanism is maintained thereof is held against an abutment |91 of the frame 45. When it is desirable to obtain temporarily a lower than normal temperature of the evaporator, the knob |85 is swung to the left whereby the point of the screw |9| is moved above its dead center position with respect to the shaft |81 and the right hand end of the screw so as to force the shoulder |98 of the segment |86 against an abutment |99 formed on the 10 frame 45. In this position the spring 264 resists the clockwise movement of the segment |86. In moving the knob |85 to its quick freezing position, the shoulder 20| thereof will engage an ear 202 on the arm 258 causing .the arm 258 and lever 6| to be raised and if the switch is not already closed, will'cause the closing of the switch.

When the knob |85 is in its extreme left hand or quick freezing position, the spring 284 will resist the downward movement of the arm 258 and lever 6| which in effect will require a low pressure in bellows 55 before the spring 65 moves y the lever 6| downwardly far enough to open the switch. In order to obtain this. low pressure in the bellows 55 the temperature in the evaporator must be lowered below its normal temperature which is a quick freezing temperature. When the spring 65 overcomes the effect of the bellows 55 and the spring 264, the switch contacts are open and the point of screw |9| will be moved to below its dead center position whereby it will tend to hold the segment |86 in the position' shown in the drawings in which position the ear 202 may freely oscillate in the groove |89. Therefore after the temporary phase of quick freezing, the system is restored to the normal control through the spring 65.

Referring particularly to Fig. 17 it will be noted that the segments |13 and |86 are interlocked. Segment |13 is formed with a projection 204 and the segment |86 /is formed with a projection 205. The projections extend toward one another and are arranged to be engaged by one another. If for example the segment |13 is in its defrosting position and it is desirable to operate the system for quick freezing, it is necess'ary only to move knob |85 to its quick freezing position. When the segment |13 is in its defrosting position it is engageable by the projection 205 of the segment |86 so that when the segment |86 is moved to its quick freezing position the projection 205 will engage projection 204 and cause the segment |13 to be restored to the position shown in Fig. 14. Likewise if the segment |86 is in its quick freezing position and it is desirable to defrost the evaporator, it is necessary only to move the knob |12 and this movement will cause the projection 204 to engage projection 205 on segment |86 and restore the segment |86 to the position shown in Fig. 15.

From the foregoing it will be apparent that there has been provided a refrigerating system in which normally a desired temperatureis maintained for proper food preservation. In case it is desirable to hasten the freezing by the evaporator or to defrost the evaporator, it is necessary only toA manually cause the starting of this temporary phase of operation and after the temporary phase of operation the system is automatically restored to the normal control.

While the forms of embodiment of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

l. In a refrigerating system comprising a cooling unit, means for circulating refrigerating medium through said unit, control means for controlling the system for maintaining the cooling unit between predetermined limits of temperature, control means forthe system for tempo-l rarily obtaining a higher temperature in the cooling unit including mechanism for temporarily modifying the operation of the circulating means and for thereafter automatically restoring the system to the normal control of the first mentioned control means, manipulating means for rendering the second named control means effective, control means for the system for temporarily obtaining a lower temperature in the cooling unit including mechanism for temporarily modifying the operation of the vcirculating means and forthereafter automatically restoring the system to the normal control of the first mentioned control means, and manipulating means for rendering the last named control means effective.

2. In a refrigerating system comprising a cooling unit, means for circulating refrigerating medium through said'unit, control means for controlling the system for maintaining the cooling unit between predetermined limits of temperature, control means for the system for temporarily obtaining either a higher or a lower temperature in the cooling unit including mechanism for temporarily modifying the operation of the circulating means and for thereafter automatically restoring the system to the normal control of the first mentioned control means, a manipulating .means for rendering the control means effective fory obtaining said higher temperature in the cooling unit, and a manipulating means for rendering the control means effective for obtaining said lower temperature in the cooling unit.

3. In a refrigerating system comprising a cooling unit, means for causing refrigerating medium to flow through said unit for maintaining said unit normally between predetermined temperature limits; and control means for the sys-' tem for temporarily rendering the rst means ineffective for the purpose of maintaining said unit normally between said predetermined temperature limits, said control means including mechanism responsive to a predetermined higher than normal temperature for restoring said system to the normal control of said first mentioned v means and including mechanism responsive to a predetermined lower than normal temperature for restoring said system to the normal control of said first mentioned means, and a plurality of manipulating means for selectively rendering either of said mechanism operative.

4. In a refrigerating system comprising a cooling unit, means for circulating refrigerating medium through said unit, control means for controlling the system'for maintaining the cooling unit between predetermined limits of temperature, control means for the system for temporarily obtaining either a higher or a lower temperature in the cooling unit including mechanism for temporarily modifying the operation of the circulating means and for thereafter automatically restoring the system to the normal control of the first mentioned control means, a manipulating'means for lrendering the control `means effective for obtaining said higher temperature in the cooling unit,a manipulating means for rendering the control means effective for obtaining said lower temperature in the cooling unit, and an interlock between said first and second mentioned manipulating means.

5. In a refrigerating system comprising a cooling unit, means for circulating refrigerating medium through said unit, control means for controlling the system for maintaining the' cooling unit between predetermined limits of temperature, control means for the system for temporarily obtaining either a higher or a lower temperature in the cooling unit including mechanism for temporarily modifying the operation of the circulating means and for thereafter automatically restoring the system to the normal control of the first mentioned control means, a manipulating means for rendering the control means effective for obtaining said higher temperature in the cooling unit, a manipulating means for rendering the control means effective for obtaining said lower temperature in the cooling unit, and an interlock between said rst and second mentioned manipulating means, said interlock including a lost motion connection.

EDWARD HEITMAN. 

